The Influence of Isotopic Mass on Some Physical Properties of Iron

[摘要] NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document.This thesis presents the results of an experimental study to determine whether atomic mass has an appreciable influence on certain physical properties of metals. Iron was chosen for this investigation, several specimens of natural iron of high purity and two specimens of iron enriched in the isotopes Fe54 and Fe57 being available.Measurements of the temperature coefficients of electric resistance between 67[degrees] and 270[degrees]K indicate an isotopic effect in qualitative agreement with deductions from the Gruneisen theory. The previous results of Tuyn may also be interpreted to give agreement with this theory and therefore are preferred to other previous work in disagreement with the theory.No isotopic influence on thermoelectric power at temperatures between 80[degrees] and 270[degrees]K is found. If such an influence does exist however, it is probably less than 0.5[...]V/[degrees]K for a thermocouple made of Fe54 and Fe57.Measurements of the temperature of the alpha-gamma allotropic transformation do not indicate an isotopic effect on this temperature. A difference of 2.5[degrees]C in the transformation temperatures of the isotopes Fe54 and Fe57 which is suggested by theoretical considerations, cannot be excluded on the basis of the present measurements, however, because of the hysteresis observed in the present study.

[发布机构] University:California Institute of Technology;Department:Engineering and Applied Science

[关键词] Mechanical Engineering and Physics